Analyze each of the following investigations, or arguments, and indicate which of the methods of causal reasoning—Mill’s methods—are being used in each of them:

Does noise have an adverse effect on those subjected involuntarily to it? When the airport at Munich, Germany, moved, researchers from the University of Hamburg, the University of Gavle in Sweden, and Cornell University took that rare opportunity to conduct a prospective study on the effects of noise, measuring the performance of students near the old airport and near the new one, before and after the move. The reading skills of students in both groups were tested, along with short-term and long-term memory, as reported in the journal Psychological Science, in October 2002. After the move, improvements in memory and reading were found among students near the old airport, while among students living near the new airport, reading skills and memory performance declined. High levels of noise do interfere with learning and development, those researchers concluded—but the brighter side of their findings was this: Most of the learning damage done by noise appeared to reverse itself when the noise was removed.